Digital television networks enable two-way communication so that a subscriber can interact or “request” information from the network equipment. Typically, a menu—also called an interactive program guide (IPG) or electronic program guide (EPG), is employed to list the content available for viewing. The IPG application enables a viewer to browse listings of available programming and associated information and to select content for viewing. The subscriber can utilize the menu to request additional information regarding the offerings.
Typically, the menu has a numeric listing by channel of broadcast television programming. Additionally, a subscriber may have access to narrowcast applications. Narrowcast programming is point-to-point streaming of video from a storage point in the network to a specific subscriber. Narrowcast applications are made possible by compression techniques such as the standards developed by the Moving Picture Experts Group (MPEG), which enables more content to be delivered to viewers with little or no degradation in picture quality. The resulting increase in transmission capacity allows narrowcast programming to be placed alongside broadcast programming for delivery to viewers.
A dominant narrowcast application is the delivery of content on demand (COD). This content may span many categories, including movies on demand (MOD), video on demand (VOD), subscription video on demand (SVOD), free on demand (FOD), and network-based digital video recording (NDVR). The ability to deliver narrowcast content to viewers creates the opportunity to provide a targeted viewing experience that allows advertisement and promotional content to be selected for and delivered to each viewer.
In a narrowcast serving environment, it is desirable that large communities of set-top boxes can access the same library of content. Typically, arrays of servers are formed to address a given set of set-top boxes and any set-top that has access to the array has access to the same set of media titles. If COD is available, the subscriber can order the content and watch it on his/her television or monitor. Otherwise, the subscriber would need to rent, purchase, or view the movie from another source.
When a customer, via his set-top box, orders a particular media title, a session is said to have been created. That session may be composed of several smaller “title sessions”—title sessions are discrete packages of content or data that collectively makeup the content requested for the overall session—e.g. one title session for the advertisement prior to the main program and another for the main program. Each title session is served by a single node on the array and all the data associated with the particular title is served through that node to a particular set-top box.
Historically, there have been several limitations to media arrays. First, the assignment of the serving of the title session to a particular node on the array makes that node a single point of failure with respect to the title session. For example, if a viewer was watching the Super Bowl on a stream being served from a node in the array and that node has a failure, then the viewer's stream would be lost and his session would be interrupted.
While the array implementations presently known in the art have collaboration between content storage devices for the purposes of reading data (e.g. RAID55, IO Shipping, and network RAID), these architectures still require that all the data pass through the assigned serving node. Thus, the serving nodes do not collaborate on the output of a single file or title session to a given client session. The serving node is therefore a single point of failure with regard to a particular client session despite the resilience of the content storage devices accessible by the serving node.
Thus, there is a need in the art for methods, systems, and apparatuses for sending content that provides for the seamless delivery of content to a user when a serving node fails. Similarly, there is a need in the art for methods, systems, and apparatuses for allocating partitioned content among two or more nodes to provide a fault resilient content delivery system.